Short circuit protection circuit for electric vehicle light control module

Abstract

The utility model discloses a short circuit protection circuit suitable for electric car lamp control module belongs to vehicle -mounted electronic protection technical field. The circuit includes power end V_BAT, and its characterized in that: the power end is connected with first amplification module, second amplification module, voltage stabilizing module and output control module respectively, the first amplification module is connected with input signal MCU_I / O, and is connected power end V_BAT through collector biasing resistance R1, through the cooperation of each stage amplification module, makes short circuit protection response time shorten to 100 microseconds within. Meanwhile, can discard traditional recoverable fuse.

Description

Technical Field

[0001] This utility model relates to a short-circuit protection circuit suitable for electric vehicle lighting control modules. Background Technology

[0002] For existing electric vehicles, different lighting control boards are used to ensure the effective opening and closing of each lighting group. However, these boards are mainly separated from the power management module of the electric vehicle and directly applied to the lighting control room, which can easily lead to the risk of local component burn-out.

[0003] For example, the electric vehicle power supply short-circuit protection circuit provided by the existing technology CN104167709A uses an enhanced NMOS field-effect transistor as the main switch and detects overcurrent signals through a sampling resistor to trigger self-locking protection. Directly incorporating it into the lamp group's on / off control would be too complex and costly to implement.

[0004] Meanwhile, the turn-off time of traditional fuses or mechanical protection solutions (such as air switches) is on the order of seconds, which cannot meet the requirement of millisecond-level rapid cut-off when the headlights are short-circuited. Summary of the Invention

[0005] The purpose of this invention is to overcome the above-mentioned problems in the existing technology and provide a short-circuit protection circuit suitable for electric vehicle lighting control modules.

[0006] To achieve the purpose of this utility model, a short-circuit protection circuit for an electric vehicle lighting control module is provided, comprising a power supply terminal V_BAT, wherein: a first amplification module, a second amplification module, a voltage regulator module, and an output control module are respectively connected to the power supply terminal; the first amplification module is connected to the input signal MCU_I / O and is connected to the power supply terminal V_BAT through a collector bias resistor R1; the second amplification module is a bipolar transistor structure, its emitter is connected to the power supply terminal V_BAT through a load resistor R2, and its collector is connected to the voltage regulator module; the output control module is a PMOS power transistor Q4, the gate of the PMOS power transistor Q4 is controlled by an NPN transistor Q3 through a current limiting resistor R8, and the drain of the PMOS power transistor Q4 is connected to the output terminal VOUT+; a short-circuit detection module is connected to the output control module, and when the output terminal is short-circuited to ground, the second amplification module is cut off.

[0007] Furthermore, in the aforementioned short-circuit protection circuit applicable to the electric vehicle lighting control module, the first amplification module is specifically an NPN transistor Q1, whose base is directly connected to the input signal MCU_I / O, whose emitter is grounded through a pull-down resistor R6, and whose collector is connected to the power supply terminal V_BAT through a 30KΩ resistor R1.

[0008] Furthermore, in the aforementioned short-circuit protection circuit applicable to the electric vehicle lighting control module, the second amplification module is composed of a PNP transistor Q2 and an NPN transistor Q3. The emitter of the PNP transistor Q2 is connected to the power supply terminal V_BAT through a 30KΩ resistor R2. The collector of the PNP transistor Q2 is connected in two paths to the base of the NPN transistor Q3 and a 15V Zener diode, respectively. The collector of the NPN transistor Q3 is connected to the gate of the PMOS power transistor Q4 through a 30KΩ drive resistor R8.

[0009] Furthermore, in the aforementioned short-circuit protection circuit applicable to the electric vehicle lighting control module, the voltage regulator module is composed of a 15V Zener diode and a 1KΩ current-limiting resistor R7 connected in series, and the voltage regulator module is connected in parallel between the output terminal of the second amplification module and the ground terminal.

[0010] Furthermore, in the aforementioned short-circuit protection circuit for electric vehicle lighting control modules, the short-circuit detection module includes an NPN transistor Q5 and a 300mΩ sampling resistor R6. The base of the NPN transistor Q5 is connected to the output terminal VOUT+, and the NPN transistor Q5 is connected to the sampling resistor R6. The collector of the NPN transistor Q5 is directly connected to the second amplification module. When the voltage difference exceeds 0.7V, the sampling resistor R6 triggers the NPN transistor Q5 to conduct, pulling the voltage of the second amplification module high to the power supply potential and then cutting it off.

[0011] Furthermore, in the aforementioned short-circuit protection circuit for electric vehicle lighting control modules, the output control module further includes an RS1G type diode D1. The anode of diode D1 is connected to the collector of NPN transistor Q3, and the cathode of diode D1 is connected to the collector of PMOS power transistor Q4, used to clamp the voltage of PMOS power transistor Q4 below 0.6V.

[0012] Furthermore, in the aforementioned short-circuit protection circuit for electric vehicle lighting control modules, the source of the PMOS power transistor Q4 is connected to the power supply terminal V_BAT, and the drain of the PMOS power transistor Q4 is connected to the output terminal VOUT- through a current-limiting resistor R5. The current-limiting resistor R5 is an adjustable power resistor with a resistance range of 50 milliohms to 2 ohms. In this way, the protection current can be adjusted according to the actual resistance value of the current-limiting resistor R5. During implementation, the current-limiting resistor R5 can be selected with a suitable resistance value as needed, making implementation more flexible.

[0013] The advantages of this utility model are: 1. Millisecond-level fast response mechanism. Through the cooperation of various amplification modules, a static operating point is established, reducing the short-circuit protection response time to less than 100 microseconds. Compared to traditional fuse solutions (typically ≥50ms), this circuit quickly shuts off after detecting a short circuit to ground at VOUT+, preventing the headlight wiring harness from melting due to continuous short-circuit current.

[0014] 2. It abandons traditional resettable fuses, eliminating the risk of mechanical contact aging. There is no risk of overheating, and the circuit performance is stable, unaffected by mechanical contact aging or resistance drift, exhibiting excellent long-term reliability.

[0015] The objectives, advantages, and features of this utility model will be illustrated and explained through the following non-limiting description of preferred embodiments, which are given by way of example only with reference to the accompanying drawings. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the short-circuit protection circuit applicable to the lighting control module of an electric vehicle. Detailed Implementation

[0017] like Figure 1 The short-circuit protection circuit shown is suitable for electric vehicle lighting control modules. It includes a power supply terminal V_BAT, which is unique in that a first amplification module, a second amplification module, a voltage regulator module, and an output control module are connected to the power supply terminal. The first amplification module is connected to the input signal MCU_I / O and is connected to the power supply terminal V_BAT through a collector bias resistor R1 (used to provide a static operating point). The second amplification module is a bipolar transistor structure; its emitter is connected to the power supply terminal V_BAT through a load resistor R2, and its collector is connected to the voltage regulator module. In practice, the output control module used in this invention is a PMOS power transistor Q4. The gate of the PMOS power transistor Q4 is controlled by an NPN transistor Q3 through a current-limiting resistor R8, and the drain of the PMOS power transistor Q4 is connected to the output terminal VOUT+. Furthermore, a short-circuit detection module is connected to the output control module. Thus, when the output terminal is short-circuited to ground, the second amplification module is cut off.

[0018] In a preferred embodiment of this utility model, the first amplification module is specifically an NPN transistor Q1, whose base is directly connected to the input signal MCU_I / O, whose emitter is grounded through a pull-down resistor R6, and whose collector is connected to the power supply terminal V_BAT through a 30KΩ resistor R1.

[0019] Meanwhile, the second amplification module used in this invention consists of a PNP transistor Q2 and an NPN transistor Q3. The emitter of the PNP transistor Q2 is connected to the power supply terminal V_BAT through a 30KΩ resistor R2. The collector of the PNP transistor Q2 is connected in two separate paths to the base of the NPN transistor Q3 and a 15V Zener diode, respectively. The collector of the NPN transistor Q3 is connected to the gate of the PMOS power transistor Q4 through a 30KΩ drive resistor R8. This achieves overall voltage regulation. Specifically, the voltage regulation module is composed of a 15V Zener diode and a 1KΩ current-limiting resistor R7 connected in series, and the voltage regulation module is connected in parallel between the output terminal of the second amplification module and the ground terminal.

[0020] Further analysis reveals that the short-circuit detection module includes an NPN transistor Q5 and a 300mΩ sampling resistor R6. The base of the NPN transistor Q5 is connected to the output terminal VOUT+. Simultaneously, the NPN transistor Q5 is connected to the sampling resistor R6. Furthermore, the collector of the NPN transistor Q5 is directly connected to the base of the PNP transistor Q2 in the second amplification module. During implementation, when the voltage difference across the sampling resistor R6 exceeds 0.7V, the NPN transistor Q5 is triggered to conduct, pulling the voltage at the base of the PNP transistor Q2 in the second amplification module high to the power supply potential, thus cutting it off.

[0021] In practical implementation, the output control module also includes an RS1G type diode D1. The anode of diode D1 is connected to the collector of NPN transistor Q3. The cathode of diode D1 is connected to the collector of PMOS power transistor Q4 to clamp the voltage of PMOS power transistor Q4 below 0.6V. Furthermore, the source of PMOS power transistor Q4 is connected to the power supply terminal V_BAT, and the drain of PMOS power transistor Q4 is connected to the output terminal VOUT- through a current-limiting resistor R5. During implementation, an adjustable power resistor with a resistance range of 50 milliohms to 2 ohms can be used to construct the current-limiting resistor R5. The default resistance value of the current-limiting resistor R5 is 300 milliohms.

[0022] This invention establishes a signal amplification path between modules via base-driven and collector-output methods. Then, through the interaction of resistors R1, R2, and R6, a static operating point is established. This achieves a response time of less than 100 microseconds. Furthermore, the circuit structure of this application eliminates the need for a resettable fuse. This avoids repeated current output and eliminates the risk of overheating.

[0023] From the implementation process of this utility model, during normal power-on, the input signal MCU_I / O is in a high state. At this time, NPN transistor Q1 turns on, followed by PNP transistor Q2, and then NPN transistor Q3. Simultaneously, the PMOS power transistor Q4 generates a voltage difference, causing it to turn on. Finally, the output terminal VOUT+ outputs the battery voltage.

[0024] If a short circuit occurs between the output terminal VOUT+ and ground GND, a voltage difference exceeding 0.7V will be generated across the pull-down resistor R6. At this time, the NPN transistor Q5 turns on, and the voltage of the PNP transistor Q2 is pulled up to near the battery voltage before turning off. Simultaneously, the NPN transistor also turns off. The PMOS power transistor Q4 does not conduct at this time due to the lack of voltage difference, and the output terminal VOUT+ is off. Therefore, due to the presence of diode D1, the voltage of the NPN transistor Q3 is clamped below the turn-on voltage of less than 0.6V until the short circuit disappears and the output resumes.

[0025] As can be seen from the above textual description and the accompanying drawings, the following advantages can be obtained by adopting this utility model: 1. Millisecond-level fast response mechanism. Through the cooperation of various amplification modules, a static operating point is established, reducing the short-circuit protection response time to less than 100 microseconds. Compared to traditional fuse solutions (typically ≥50ms), this circuit quickly shuts off after detecting a short circuit to ground at VOUT+, preventing the headlight wiring harness from melting due to continuous short-circuit current.

[0026] 2. It abandons traditional resettable fuses, eliminating the risk of mechanical contact aging. There is no risk of overheating, and the circuit performance is stable, unaffected by mechanical contact aging or resistance drift, exhibiting excellent long-term reliability.

[0027] Of course, the above embodiments are only for illustrating the technical concept and features of this utility model, and their purpose is to enable those skilled in the art to understand the content of this utility model and implement it accordingly. They should not be used to limit the protection scope of this utility model. All modifications made in accordance with the spirit and essence of the main technical solution of this utility model should be covered within the protection scope of this utility model.

Claims

1. A short-circuit protection circuit suitable for electric vehicle lighting control modules, comprising a power supply terminal V_BAT, characterized in that: The power supply terminal is respectively connected to a first amplification module, a second amplification module, a voltage regulator module and an output control module; the first amplification module is connected to the input signal MCU_I / O and is connected to the power supply terminal V_BAT through the collector bias resistor R1; The second amplification module is a bipolar transistor structure, with its emitter connected to the power supply terminal V_BAT through the load resistor R2, and its collector connected to the voltage regulator module. The output control module is a PMOS power transistor Q4. The gate of the PMOS power transistor Q4 is controlled by an NPN transistor Q3 through a current-limiting resistor R8. The drain of the PMOS power transistor Q4 is connected to the output terminal VOUT+. The output control module is connected to a short-circuit detection module. When the output terminal is short-circuited to ground, the second amplification module is turned off.

2. The short-circuit protection circuit for electric vehicle lighting control modules according to claim 1, characterized in that: The first amplification module is specifically an NPN transistor Q1, whose base is directly connected to the input signal MCU_I / O, whose emitter is grounded through a pull-down resistor R6, and whose collector is connected to the power supply terminal V_BAT through a 30KΩ resistor R1.

3. The short-circuit protection circuit for electric vehicle lighting control modules according to claim 1, characterized in that: The second amplification module consists of a PNP transistor Q2 and an NPN transistor Q3. The emitter of the PNP transistor Q2 is connected to the power supply terminal V_BAT through a 30KΩ resistor R2. The collector of the PNP transistor Q2 is connected to the base of the NPN transistor Q3 and a 15V Zener diode respectively. The collector of the NPN transistor Q3 is connected to the gate of the PMOS power transistor Q4 through a 30KΩ drive resistor R8.

4. The short-circuit protection circuit for electric vehicle lighting control modules according to claim 1, characterized in that: The voltage regulator module is composed of a 15V Zener diode and a 1KΩ current-limiting resistor R7 connected in series. The voltage regulator module is connected in parallel between the output terminal of the second amplifier module and the ground terminal.

5. The short-circuit protection circuit for electric vehicle lighting control modules according to claim 1, characterized in that: The short-circuit detection module includes an NPN transistor Q5 and a 300mΩ sampling resistor R6. The base of the NPN transistor Q5 is connected to the output terminal VOUT+, and the NPN transistor Q5 is connected to the sampling resistor R6. The collector of the NPN transistor Q5 is directly connected to the second amplification module. When the voltage difference exceeds 0.7V, the sampling resistor R6 triggers the NPN transistor Q5 to conduct, pulling the voltage of the second amplification module up to the power supply potential and then cutting it off.

6. The short-circuit protection circuit for electric vehicle lighting control modules according to claim 1, characterized in that: The output control module also includes an RS1G type diode D1. The positive terminal of the diode D1 is connected to the collector of the NPN transistor Q3, and the negative terminal of the diode D1 is connected to the collector of the PMOS power transistor Q4, which is used to clamp the voltage of the PMOS power transistor Q4 below 0.6V.

7. The short-circuit protection circuit for electric vehicle lighting control modules according to claim 1, characterized in that: The source of the PMOS power transistor Q4 is connected to the power supply terminal V_BAT, and the drain of the PMOS power transistor Q4 is connected to the output terminal VOUT- through the current limiting resistor R5; the current limiting resistor R5 is an adjustable power resistor with a resistance range of 50 milliohms to 2 ohms.

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